Bay is the sixth region of Somalia to slip into famine since the UN's initial declaration of famine in the war-torn country in July that has left 4 million Somalis, or 53% of the population, unable to meet their food needs.

Hundreds of people are dying each day and at least half of them are children, the UN' Grainne Moloney said, adding she expected the remaining regions of southern Somalia to slip into famine by the end of the year.

'The rate of malnutrition (among children) in Bay region is 58%. This is a record rate of acute malnutrition,' said Moloney, the chief technical advisor for the UN Food Security and Nutrition Analysis Unit.

Aid agencies are only able to get food aid to 1 million of those in need because the al-Qaeda-affiliated rebel group, al-Shabaab, which controls much of the south, will not allow food shipments in.

Instead, agencies are using food and cash vouchers which hungry families can exchange for commodities in local markets.

Somalia is at the epicentre of a hunger crisis in the Horn of Africa region which is affecting over 13 million people.

Famine exists where at least 20% of households cannot access enough food, over 30% are acutely malnourished and two people per 10,000 die every day, according to the UN.